With all due respect, Lemaster, I have used this technique for over 30 years and if there is distortion there, I cannot see it. I have heard this claim over and over but Omega never allowed for above the condenser filter installation and for me it is a non-issue. More to the point that it may be a old photographers tale. Stated but never proved. If you have postive evidence, I would like to see it. As for the red filter holder on the side, that is my understanding also.